Custom colour swatches shows black in colour picker box.

Guys, m having the most annoying problem, because I found no single solution in Google aswell as in any social media groups.

When I use the inbuilt color swatches from the app itself, I face no problem. But when I create my own custom colour swatches sampling from a photos by using eye dropper tool, then I faced such problems. For highlighting and shadowing I would be needing a light and dark colour from my base colour, eg- suppose my object colour is green, I would be needing a lighter green for highlights and darker green for shadows and for that I need to use colour picker , but the main problem is that the colour picker shows black, also I can't use the slider from colour option, and that's one of the most annoying thing, I would like to share few screenshots.....(sorry my English is not that good, but I hope you guys understood what I meant)...